Basic rules for clothing
1. Only make the cloth mesh as dense as neccesary
2. Make sure the collider has enough definition
3. For fabric use very small flexion and high stiffness values
4. Make the eps settings depending on the object size
5. Don't use specular materials if you don't want a rubber like look
6. Use as few polygons as possible
7. Choose correct size
8. Optimal topology
1. If you want small creases you will need higher subdivisons, for anything else try to make the cloths polygon size as big as possible while still beeing able to bend enough for the needed purpose.
Don't forget, a single polygon can not be bend.
This becomes very visible when doing the old cloth on a table routine. You can either bevel the table or use (much) higher subdivided cloth. Usualy beveling or the use of a beveled proxy is the better way.
2. In a HN even a very low poly model will look smooth and fine, but the cloth collision will only work on the real polygon mesh, not on the HyperNURBS. Make sure the collider is round enough so you don't see the underlying structure through the cloth.
3. Real fabric has very low Flexion forces. You can easily bend it to small radiuses. In Clothilde this is reflected by the Flexion setting. Values smaller then 5% will do fine. Also common fabric is rather stiff (will not elongate much when pulled). Using Stiffness values of 100% or above will ensure this.
4. EPS (Epsilon) values determine the area around a surface in which a collssion will be detected. Usualy this should be set to values of 1/10 - 1/100 of the object size.
Polygon EPS < Edge EPS < Point eps
If the colliding meshes are equaly subdivided you might only need point or edge collission, thous speeding up calculation.
5. Regardless of the physical behaviour of your cloth it will most likely look like rubber if you use materials with speculars. If possible use textures and bump maps to give the cloth structure and a more natural appeal.
6. The number of polygons in the cloth and collider determine the speed of caluclation. Always try to use only as much as needed. If neccesary replace the original collider object with a low poly proxy. This might conflict with rule 2. A combination of 0 subdivisions ClothNURBS and HyperNURBS for the cloth might help to smooth out minor problems.
7. When modelling the original cloth you have to keep the largest possible elongation in mind. If you create a skirt you have to model it so there is enough material to allow for leg movement. Especialy with long dresses this can be a real problem if you try to keep the fit tight and then create large leg movements. The only other solution for this is to allow for stretching (lower stiffness and higher rubber values. Stretching will show very obviously though.
8. To create predictable and visualy appealing folds and bending try to use polygons that are equal in size and as square as possible. A square plane will give very good results while a disc with the very differently sized segments and edge lengthes will easily lead to problems.